This invention belongs to the field of technology relating to electric golf carts that carry a single caddie bag for a player over a golf course.
There are many conventional techniques for electric one-bag golf carts that carry a caddie bag for a player over a golf course, (for example, Japanese Patent Disclosure No. H9 (1997)-28847, Japanese Patent Disclosure No. H8 (1996)-229173, etc.).
The principal features common to these carts are that they are simply hand-pushed carts that have been provided electric power and they have old and unrefined designs consisting of a box-shaped chassis and handlebars made of circular metal rods. On the other hand, golf carts that have been given artistic elaboration with regard to the shape of the cart body and other parts are well known, as disclosed in Japanese Registered Design No. 1102885 issued to the present applicant.
But now golf is widely recognized as a social occasion, and with the number of female golf players increasing, golf has become a more sophisticated and fashionable pastime. Golf carts can no longer be old-fashioned, rough-styled machines that work only as carriers of golf bags. It is obvious that only fashionable golf carts that can match the beautiful of the fairways will give satisfaction to players. In that sense, the golf cart of the above mentioned Design Registration No. 1102885 perfectly meets these needs.
The object of the present invention is to provide a practical electric golf cart by embodying such design.
Were the general, conventional injection molding employed to form the cart body according to such design using synthetic resin, it would be impossible to mold the whole body as an single, integral piece. Based on the design facility of molds, it would seem inevitable that the body would have to be molded in at least three separate pieces. Even in such case, the molds would be complex and expensive. Moreover, very large injection molding machines would be required, resulting in high running costs. Further, various processes would be needed to attach the various parts to the molded pieces and to assemble them into a cart body, all in all resulting in a very expensive golf cart.
Additionally, some kinds of synthetic resin would present recycling and disposal problems. At the least, vinyl chloride and the like should not be used. Further, since the carts are used being exposed to strong sunlight, wind and rain, the issue of weatherproofing should also be taken into consideration.
Next, since golf players vary greatly in physical size, (especially height), for example, among children and grown-ups, men and women, and so on, electric golf carts, especially ones used for a single golf bag, should be constructed of a size that would allow them to be used easily by all kinds of players; preparing golf carts of various sizes would too much cost. The steering device on a conventional golf cart is usually designed simply as to be located at one level, and do not take into consideration the differences in physical sizes of players. Further, positional coordination between the speed controller for controlling the cart speed and the steering device is not adequate in conventional models. In addition, since the speed controller is generally of a knob type and its operational capability is rather poor, it is difficult to manipulate the controller while gripping the bars of the steering device.
The object of the present invention is to provide a golf cart for a single bag that has a cart body molded from the polyolefin family of plastics, in a single piece, using the rotational molding method. Such a golf cart is inexpensive, because it dispenses with the assembling process for the body, is easy to use, has no serious recycling or disposal problems, and is strong and weatherproof
The next object of the present invention is to provide a golf cart for a single bag that can be used comfortably by various golf players, regardless of their physical size, and a golf cart the speed of which can be controlled easily while the steering device is being gripped by the golfer.
The electric one-bag golf cart according to the present invention is characterized in that the whole cart body, including the chassis, the neck part arising from the chassis and the steering device portion located at the top of the neck, is formed as an integral single hollow piece using the rotational molding method. The electric one-bag golf cart is further characterized in that the wheel system under the chassis consists of one front wheel and two rear wheels, with the front wheel mounted pivotally on a suspension, while the rear wheels are driving wheels using a differential gear device driven by a motor. The electric one-bag golf cart according to the present invention has a battery and a control board mounted in a battery chamber formed on the chassis together with a lid that can be freely opened and closed. The electric one-bag golf cart also has a speed control dial at the center of the steering device, made of circular rods, and a brake lever located under the steering device, together with a locking device.
In the electric one-bag golf cart according to the present invention, the steering device consists of lower grip parts, which extend backward on both sides and curved downward, and upper grip parts, which are curved upward from the corners where the rods are bent and are connected to the core portion of the steering device part where the speed controller is located.
The electric one-bag golf cart according to the present invention is further characterized in that the control board contains a micro-processing unit that checks the voltage level of the battery using digital signals. Signals from the speed controller are also converted into digital signals and sent to the micro-processing unit, where the cart speed is controlled by signals from the speed controller. The micro-processing unit sends driving signals to the motor driving circuit in order to make the calculated revolution rate of the wheels, traveling over the ups and downs of the golf course, approximately agree with the actual revolution rate as detected by a revolution sensor for the motor. The brake lever has a brake switch through which the driving signals to the motor are switched over to turn off the driving signals. The lock mechanism has a brake lock switch and, as the brake lever is locked, the micro-processing unit displays a locked status notice on the LED display device.
The electric one-bag golf cart according to the present invention has a body that is formed as an integral single hollow piece by utilizing the rotational molding method, which means that the structure of the molds is relatively simple and the cost to mold the body can be kept low. Further, since this molding method does not require particular pressure, no particularly large and high performance molding machines are needed, which means the facilities investment costs and the running costs can also be kept low, again contributing to low molding costs for the cart body. These features contribute to providing low-priced golf carts.
Since the cart body is formed as an integral single hollow piece, not only is it light-weight and uses less resin material, it is also almost free from assembling processes, does not give rise to the structural and strength problems due to seam lines, is easy to produce and can contribute to providing golf carts of excellent design, all of which will satisfies golfers.
Moreover, the feature of the rotational molding method has another advantage in that it provides adequate strength for the cart body because this method gives greater thickness at the corners of the golf cart body. Adoption of the polyolefin family of plastics, which can be easily disposed of or recycled, as the material for the cart body means that environment-friendly and yet colorful golf carts can be provided. Since this material is excellent in terms of being weatherproof, the golf cart does not greatly deteriorate in quality or discolor due to ultra-violet rays or rough weather.
The cart can be operated from a natural posture by golf players of various heights, with shorter players using the lower grip parts and taller players using the higher grip parts. Therefore, all players, regardless of differences in physical size, such as the differences among grown-ups and children, men and women, and so on, can use the cart comfortably. Further, the cart is user-friendly in that the speed controller and the brake lever can be manipulated by one hand while the steering device is being held.
The golf cart is controlled to run at the speed determined by the speed controller, regardless of the topography of the course, making the operation of the cart easy and comfortable for the player. When the brake of the cart is locked, the player can see the locked status visually on the display, and the player can concentrate on his or her play without having to worry about unexpected movements of the cart.